Methods And Devices For Creating Electrical Block At Specific Targeted Sites In Cardiac Tissue

ABSTRACT

The present invention provides a mechanical injury device having cutting elements for injuring tissue and thereby creating electrical block that can prevent atrial fibrillation. These cutting elements may preferably be removable, breakaway, or simply integral to the injury device and may be delivered, for example, by catheter or hand tool.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application60/467,298, entitled Improved Methods And Devices For CreatingElectrical Block At Specific Targeted Sites In Cardiac Tissue, filed May1, 2003, the entire contents of which are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

Pumping of the human heart is caused by precisely timed cycles ofcompartmental contractions of the heart muscle which lead to anefficient movement of blood into the heart and out to the various bodilyorgans and back again to the heart. These precisely timed cycles arecontrolled and directed by electrical signals that are conducted throughthe cardiac tissue and can be referred to as pacing signals.

The sinoatrial node (SA node) is the heart's natural pacemaker, locatedin the upper wall of the right atrium. The SA node spontaneouslydepolarizes and generates electrical impulses that travel throughout theheart wall causing both the left and right atria to sequentiallycontract according to a normal rhythm for pumping of the heart. Theseelectrical impulses continue to the atrioventricular node (AV node) anddown a group of specialized fibers called the His-Purkinje system to theventricles. This electrical pathway must be exactly followed for properfunctioning of the heart.

When the normal sequence of electrical impulses changes or is disrupted,the heart rhythm often becomes abnormal. This condition is generallyreferred to as an arrhythmia and can take the form of such arrhythmiasas tachycardias (abnormally fast heart rate), bradycardias (abnormallyslow heart rate) and fibrillations (irregular and typically quite rapidcardiac electrical activity).

Of these abnormal heart rhythms, fibrillation, and particularly atrialfibrillation, is gaining attention by clinicians and health workers.Atrial fibrillation develops when a disturbance in the electricalsignals causes the two upper atrial chambers of the heart to quiverinstead of function as a synchronized pump. When this happens, blood isnot efficiently pumped from the atrial chambers, thus creating asituation where the blood may pool and even clot inside the atria. Suchclotting can be very serious insofar as the clot can, for example, leavethe atrial chamber and block an artery in the brain or coronary artery,and thereby cause a stroke or heart attack in the individual.

A variety of treatments have been developed over the years to treatatrial fibrillation, namely, treatments to either mitigate or eliminateelectrical conduction pathways that lead to the arrhythmia. Thosetreatments include medication, electrical stimulation, surgicalprocedures and ablation techniques. In this regard, typicalpharmacological treatments have been previously disclosed in U.S. Pat.No. 4,673,563 to Berne et al.; U.S. Pat. No. 4,569,801 to Molloy et al.;and also by Hindricks, et al. in “Current Management of Arrhythmias”(1991), the contents of which are herein incorporated by reference.

Surgical procedures, such as the “maze procedure”, have also beenproposed as alternative treatment methods. The “maze” procedure attemptsto relieve atrial arrhythmias by restoring effective atrial systole andsinus node control through a series of incisions.

The maze procedure is an open heart surgical procedure in whichincisions are made in both the left and right atrial walls whichsurround the pulmonary vein ostia and which leave a “maze-like” pathwaybetween the sino-atrial node and the atrio-ventricular node. Theincisions are sewn back together but result in a scar line which acts asa barrier to electrical conduction.

Although the “maze” procedure has its advantages, in practice it can becomplicated and a particularly risky procedure to perform since thesurgeon is making numerous physical incisions in the heart tissue. Duein part to the risky nature of the maze procedure, alternative,catheter-based treatments have been advanced. Many of these catheterdevices create the desired electrical block using ablation devicesdesigned to scarred lesions by burning, freezing, or other noxiousmethods directed at target tissue. Examples of these devices can be seenin U.S. patents: U.S. Pat. No. 6,254,599 to Lesh; U.S. Pat. No.5,617,854 to Munsif; U.S. Pat. No. 4,898,591 to Jang et al.; U.S. Pat.No. 5,487,385 to Avitall; and U.S. Pat. No. 5,582,609 to Swanson, allincorporated herein by reference.

Although ablation catheter procedures remain less invasive than previoussurgical methods like the “maze” procedure, they nevertheless retain asignificant element of risk. For example, ablation procedures oftenutilize high power RF energy or ultrasonic energy, which may adequatelycreate electrical block, but their inherent destructive nature allowsfor the possibility of unintended damage to the target tissue or nearbyareas.

More recently, implantable devices have been used near or within thepulmonary vein to cause electrical block, as seen in the pending andcommonly owned U.S. patent application Ser. No. 10/192402 entitledAnti-Arrhythmia Devices And Methods Of Use, filed Jul. 8, 2002, thecontents of which are incorporated by reference. Once implanted, thesedevices cause injury to target tissue near the ostium of the pulmonaryvein but often do not create an acute electrical block. Rather, theelectrical block may develop as the healing process runs its course onthe injury. Other examples of such devices are seen in the pendingcommonly owned U.S. patent application Ser. No. 10/792,111 entitledElectrical Block Positioning Devices And Methods Of Use Therefor, filedMar. 2, 2004, the contents of which are hereby incorporated byreference.

However, controlling the injury caused by the implant device can remaindifficult since these techniques often require the implant device toremain in the patient permanently. Further, it can be difficult for animplant device to securely fit at a desired position within a patient,especially near the ostium of a pulmonary vein. What is needed is adevice that can create controlled damage such as is caused by apermanent implant but without the drawbacks of a permanent implant.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide an easily controlledmechanical injury device to create electrical block within an atrium orpulmonary venous region of a patient.

It is another object of the present invention to provide a mechanicalinjury device that reliably creates lines of electrical block in anatrial or pulmonary vein region of a patient.

It is a further object of the present invention to overcome thelimitations of the prior art.

The present invention achieves these objectives by providing amechanical injury device having cutting elements for injuring tissue inthe patient and thereby creating electrical block. These cuttingelements may be removable, breakaway, or simply integral to the injurydevice and may be delivered, for example, by a catheter or hand tool.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of a forward injury arm catheteraccording to the present invention;

FIG. 2 illustrates a side view of a reverse injury arm catheteraccording to the present invention;

FIG. 3 illustrates a side view of a bent injury arm catheter accordingto the present invention;

FIG. 4A illustrates a perspective view of a roller head according to thepresent invention;

FIG. 4B illustrates a perspective view of a cutting element according tothe present invention;

FIG. 4C illustrates a perspective view of a cutting element according tothe present invention;

FIG. 5 illustrates a perspective view of a roller head delivery assemblyaccording to the present invention.

FIG. 6 illustrates a top view of a flattened roller head according tothe present invention;

FIG. 7 illustrates a top view of a flattened roller head according tothe present invention;

FIG. 8 illustrates a top view of a flattened roller head according tothe present invention;

FIGS. 9A-9F illustrate various views of a removable cutting elementaccording to the present invention;

FIGS. 10A-10D illustrate various views of a breakaway cutting elementaccording to the present invention;

FIGS. 11A-11B illustrate various views of a hand-held injury deviceaccording to the present invention;

FIG. 12 illustrates a perspective view of a hand-held injury deviceaccording to the present invention;

FIG. 13 illustrates a side view of an expandable mesh injury deviceaccording to the present invention;

FIG. 14 illustrates a side view of a cutting element deployment catheteraccording to the present invention;

FIG. 15 illustrates a side view of the deployment arm illustrated inFIG. 14; and

FIG. 16 illustrates a side view of the hub for the cutting elementdeployment catheter illustrated in FIGS. 14 and 15.

DETAILED DESCRIPTION OF THE INVENTION

The present invention contemplates the use of cutting elements such asneedle or pin shapes to cause injury to desired target tissue. Thetarget tissue is typically the atrial tissue surrounding the ostia of apulmonary vein, however, it can also include tissue inside the ostia ortissue inside the pulmonary vein downstream of the ostia. The injuryresults in scarring of the target tissue and the scarred tissue resultsin the formation of a conduction block that prevents the aberrantsignals from causing the atrial fibrillation. One method of efficacy maybe to introduce hemorrhage within the wall of the target tissue thattypically heals with a non-electrically active scar. As described below,the cutting elements may preferably be integral with the device,allowing for one-time injury, or the cutting elements may alsopreferably be removable or breakaway, allowing for prolonged tissuedamage.

As described elsewhere in this application, these cutting elements maybe preferably deployed with a variety of different devices, such as aroller head on a catheter or hand held tool, an expandable catheter, orby way of a deployment tube. Thus, a user is better able to create acontrolled, desired injury to a patient, resulting in a potentiallysafer procedure and the formation of a more precise electricalconduction block.

Injury Arm Catheter

FIG. 1 illustrates a preferred embodiment of a forward injury armcatheter 116 according to the present invention as deployed in apulmonary vein 102. The forward injury arm catheter 116 has a forwardinjury arm 110 with a roller head 112 fixed to a catheter body 108.Disposed on the roller head 112 are cutting elements 113 which may bedirected to cause injury at a desired target site.

The catheter body 108 has an inner lumen (not shown) sized for a guidewire 114 which may assist a user in positioning the forward injury armcatheter 116 at a desired location, e.g. in a pulmonary vein 102 orpulmonary vein ostial opening 100. Near the distal end of the catheterbody 108 is forward injury arm 110 which, at one end, is fixed to thecatheter body 108 and extends radially and distally away from thecatheter body 108 when deployed. The forward injury arm 110 ispreferably preset to expand radially away from the catheter body 108, toa position similar of that seen in FIG. 1.

The roller head 112 is coupled to the distal end of forward injury arm110 so as to freely axially rotate. As best seen in FIGS. 4A and 4B, pinshaped cutting elements 113 located around the circumference of theroller head 112 are preferably angled perpendicularly away from theroller head 112. Preferably, the roller head 112 may be formed from asmall section of hypotube or a similar tube shape composed of a rigidmetal or plastic material. A desired pin pattern may be laser cut intothe perimeter of the tube and the cutting elements 113 can be formed toproject out from the surface of the tube. A variety of different shapesand patterns of cutting element 113 may be used on the roller head 112,examples of which are discussed elsewhere in this application.

In operation, the guide wire 114 is inserted within a patient's vesseland positioned at a desired target location, for example, the guide wire114 may be transeptally positioned within a pulmonary vein 102 of a leftatrium 104. The catheter body 108, the forward injury arm 110 and theroller head 112 are packed within the transeptal sheath 106 to reduceunintended injury to non-target areas of the patients vessels. This canbe accomplished with a thin-walled sleeve 107, seen best in FIG. 5,which holds the roller head 112 down to a compressed diameter forpassage through the transeptal sheath 106 and the atrium. This sleeve107 also shields the cutting elements 113 from damaging the transeptalsheath 106 in transit. The sleeve 107 is retractable to release theroller head 112 from its compressed diameter when ready to advance theroller head 112 into position at the targeted treatment site. Next,forward injury arm catheter 116 is advanced along the guide wire 114 toa desired target location, e.g. a pulmonary vein 102 or the ostialopening 100 of a pulmonary vein. The sleeve 107 is pulled back,uncovering a portion of the catheter body 108 and forward injury arm110. The forward injury arm 110 expands away from the catheter body 108until the roller head 112 contacts the target tissue, causing cuttingelements 113 to create points of injury. The catheter body 108 is thenrotated, which causes the forward injury arm 110 and the roller head 112to move in a circular path around the inside of pulmonary vein 102. Theroller head 112 itself rotates axially, reducing resistance andfacilitating the overall rotational movement of the catheter body 108and forward injury arm 110. Thus, the injury elements 113 on the rollerhead 112 may cause a continuous, circular line of electrical block asthe injury heals and forms scar tissue. The forward injury arm 110 maybe repositioned to repeat the injury in other locations to achieve adesired electrical block. When the user is finished, the roller head 112can be compressed back within the sleeve 107 after completing treatmentby advancing the sleeve forward. This can be facilitated by the shape ofthe injury arm 110 and by angling the first row of cutting elements 113as shown in FIG. 5. The forward injury arm catheter 116 can then beremoved through the transeptal sheath 106. In a preferred embodiment theroller head 112 and cutting elements 113 will have a diameter of about0.100 inches or less to allow it to be compressed down against thecentral catheter lumen and still allow it to be sleeved and fit inside a10-11 French sheath.

FIG. 2 illustrates a preferred embodiment of a reverse injury armcatheter 120, having an overall similar design to the previousembodiment. However, the reverse injury arm catheter 120 has a reverseinjury arm 122 fixed to a distal end of the catheter body 108 andextends in a proximal direction (an opposite direction to the preferredembodiment of FIG. 1). The reverse injury arm 122 is preset to move awayfrom the catheter body 108 when in a deployed state, pressing the rollerhead 112 against the inner surface of pulmonary vein 102. The reverseinjury arm catheter 120 may include a tether wire (not shown) having oneend fixed to the reverse injury arm 122 and passing into a lumen (notshown) within the catheter body 108. With this tether wire, a user maymove the reverse injury arm 122 close to the catheter body 108, allowingthe transeptal sheath 106 to be slid over both the reverse injury arm122 and the remaining exposed portion of the catheter body 106.

The reverse injury arm catheter operates in a manner similar to theprevious embodiment of FIG. 1, namely the guide wire 114 is initiallypositioned at a target location, followed by the transeptal sheath 106containing the catheter body 108, the reverse injury arm 122 and rollerhead 112. Once in position, the transeptal sheath 106 is movedproximally to expose the reverse injury arm 122 and roller head 112.Once deployed, the reverse injury arm 122 moves outward from thecatheter body 108, axially, until the roller head 112 contacts thetarget area, e.g. the inside of the pulmonary vein 102 or the ostialopening 100 of the pulmonary vein 102. The catheter body 108 is rotatedby the user, moving the reverse injury arm 122 and roller head 112around the ostium 100 in a circular path. After at least one completerotation, the cutting elements 113 have formed a continuous circularline of injury which gradually creates a line of electrical block as aresult of forming scar tissue in the healing process.

FIG. 3 illustrates a preferred embodiment of a bent injury arm catheter130, generally similar to the preferred embodiment of FIG. 2. However,the bent injury arm catheter 130 differs in that it has an injury arm122 with a preset curve and a roller head 132 with an overall roundedshape.

The injury arm 133 may be formed with varying preset bends, depending onthe desired target area. For example, the injury arm 133 of FIG. 3illustrates a bend appropriate to reach the ostium 100 of a pulmonaryvein 102 when deployed. The roller head 132 has an overall rounded shapewith cutting elements 134 disposed upon the surface. This injury arm 133and roller head 132 combination allow the bent injury arm catheter 133to create continuous lines of injury in locations otherwise perhaps hardto achieve by the preferred embodiments illustrated in FIGS. 1 and 2.

Cutting Elements

The cutting elements described in this application may take a variety ofshapes and patterns, as seen in the preferred embodiments of FIGS.4A-10D. Cutting elements may be configured to cause varying levels oftissue damage, for example, or to create multiple lines of injury withvarying length, width, and spacing. It is desirable to create localbleeding into the tissue wall without creating significant bleedingthrough the wall. In one preferred embodiment of the cutting elementsused for the pulmonary vein 102 may be about 0.050 inches in length,about 0.015 inches in width and about 0.015 inches in thickness.Further, theses cutting elements may be composed from a wide range ofpossible materials, such as metals, engineering polymers, biodegradablepolymers, or drug eluting polymers, depending on the needs of the user.

FIGS. 4B and 4C illustrate examples of two preferred embodiments ofcutting elements 113 and 140. Cutting element 113 has an elongated pinshape while cutting element 150 includes two side barbs. These shapesmay be further modified by, for example, varying the cutting elementthickness, width, length, profile shape, and composition.

FIGS. 9A-9F illustrate a further preferred embodiment of removablecutting element 162 according to the present invention wherein thecutting elements 162 remain fixated in the target tissue and therebycreate additional injury at the target site. The removable cuttingelement 162 has a sharp, barbed point 162 a at one end and a lockingring 162 b at the other. The cutting element post 160 consists of anupwardly positioned post having two prongs, each of which has aprotrusion 160 a. The locking ring 162 b of the removable cuttingelement 162 slides onto cutting element post 160, past the protrusions160 a, and locking in place as seen best in FIG. 9C.

FIGS. 9D-9F illustrate the removable cutting element 162 in operation ona roller head 164. The removable cutting element 162 is initially lockedonto cutting element post 160 which is then directed into an area oftarget tissue by roller head 164 rolling over the target tissue. Theremovable cutting element 162 penetrates the target tissue by therolling force of roller head 164. As the roller head 164 rolls away fromthe penetration point, the barbs 162 a hold the cutting element 162within the tissue, allowing the cutting element post 160 to pull out oflocking ring 162 b, leaving the cutting element 162 in the targettissue.

FIGS. 10A-10D illustrate yet another preferred embodiment of a breakawaycutting element 170 according to the present invention which breaks offduring a procedure within a target tissue to create further injury. Thebreakaway cutting elements 170 are composed of a base 170 b and abreakaway barbed tip 170 a. An aperture 170 c is located between thebase 170 b and the barbed tip 170 a to encourage the barbed tip 170 a tobreak off of the base 170 b when placed in tension.

FIGS. 10B-10D illustrate the breakaway cutting elements 170 in operationas part of roller head 164. The roller head 164 rolls over a targettissue, forcing the barbed tip 170 a into the tissue. As the roller headcontinues rolling, base 170 b pulls against the anchoring force of thebarbed tip 170 a, and further breaks away from the barbed tip 170 a.Thus, the barbed tip 170 a is left within the target tissue to cause adesired amount of damage and consequently causing electrical block.

FIGS. 6-8 illustrates various preferred embodiments of example cuttingelement patterns. These figures illustrate example roller heads in a“flattened” view with patterns created with cutting lasers, chemicaletching or similar fabrication techniques.

Looking first to a preferred embodiment illustrated in FIG. 6, cuttingelements 142 are elongated needle shapes arranged in two closelypositioned rows. FIG. 7 illustrates a dual row variation according tothe present invention with one set of cutting elements 146 formed bybending the base 146 a of the cutting element 146 and one set ofelements 144 formed up by twisting the bar 144 a of material at the baseof the cutting element 144. FIG. 8 shows the same types of cuttingelements as shown in FIG. 7, having a row of cutting elements 150 formedby bending the base 150 a and a row of cutting elements 148 formed bytwisting the bar 148 a of material at the cutting element 148 base.,both of which are less densely spaced than the rows of FIG. 7.

Hand Held Injury Device

Turning now to FIGS. 11A and 11B, a preferred embodiment of a hand-heldinjury device 180 is illustrated according to the present invention,including a roller head 186 attached to a handle 182. This hand-heldinjury device 180 allows a user to create injury to a patient at anostial opening 100 of a pulmonary vein 102 of the left atrium 104 asshown in FIG. 11A during surgical procedures that expose a desiredtarget tissue, e.g. a mitral valve repair procedure. Alternatively, thehand-held injury device 180 may also be used during procedures where theleft atrium is not open, e.g. in connection with coronary artery bypassgraft (CABG) procedure. In this case the device would be used on theepicardial surface of the heart.

The roller head 186 has cutting elements 188 disposed along the outerdiameter of its surface and is further rotationally mounted to arm 184.At the opposite end of arm 184 is handle 182.

In operation, a user grasps the handle 182 and directs the roller head186 to the target tissue area (e.g. ostium 100 of the pulmonary vein102) and rolls a continuous line where electrical block is desired. Inthis respect, the hand-held injury device 180 functions in a similarfashion to a pizza cutter, allowing for a narrow band of injury.

FIG. 12 illustrates yet another preferred embodiment of a hand-heldinjury device 109 according to the present invention. A cylinder rollerhead 196 similar to the embodiment of FIG. 4A is rotatably mounted toarm 194 with a handle 192. The outer diameter surface of cylinder rollerhead 196 is disposed with cutting elements 198, allowing for a largerinjury area compared to the preferred embodiment of FIG. 11A.

To operate, a user simply grasps the handle 192 and positions the rollerhead 196 against the desired target area (e.g. the ostium 100 of thepulmonary vein 102), pressing the cutting elements 198 into the tissueto create a line of injury that results in an electrical block.

Expandable Mesh Injury Catheter

FIG. 13 depicts yet another preferred embodiment of a mesh injurycatheter 200 according to the present invention, including cuttingelements 208 fixed to the outer circumference of an expandable meshsection 204. Like many prior art catheters, the present preferredembodiment includes a guide wire 206 that may be positioned through aninner lumen of catheter body 202, allowing the guide wire 206 to beadvanced to a desired target location within a patient (e.g. within apulmonary vein 102), followed by the catheter body 202.

The expandable mesh section 204 is composed of elongated elements,preferably metal, woven together into a mesh. The distal end 207 of meshsection 204 is connected to a control cable within the catheter body 202and is not connected to the catheter body 202. Thus, when a user pullsthe control cable, the distal end 207 of expandable mesh section 204moves in a proximal direction, expanding the mesh section 204 againstthe surrounding tissue. Since the cutting elements 208 are located onthe outer surface of the expandable mesh section 2-4, the cuttingelements 208 are pushed into the surrounding tissue, causing injury. Inthis manner, a user may position the distal end of the mesh injurycatheter 200 at a desired location (a pulmonary vein 102 of a leftventricle, for example) to cause damage and ultimately a continuous lineof electrical block.

Cutting Element Deployment Catheter Arm

Referring to FIGS. 14 and 15, a preferred embodiment of a cuttingelement deployment catheter 210 can be seen according to the presentinvention. The cutting element deployment catheter 210 contains acutting element deployment arm 216, seen best in FIG. 15, that may bepositioned at a desired position within a patient to deploy cuttingelements 218 to cause tissue injury.

The expandable mesh anchoring section 220 is located at the distal endof catheter body 214, having a similar structure to the expandable meshsection 202 of FIG. 13, with the exception of cutting elements 208.Thus, the expandable mesh anchoring section 220 expands at a desiredlocation (e.g. a pulmonary vein 102), anchoring the cutting elementdeployment catheter 210 at a desired location.

The cutting element deployment arm 216 is positioned adjacent tocatheter body 214, within an inner sheath 212, and can be advanced orretracted relative to the catheter body 214. As best seen in FIG. 15,cutting element deployment arm 216 contains longitudinally alignedcutting elements 218 with a driver rod 222 positioned proximal to thestack of cutting elements 214. The driver rod 222 may be advanced by theuser from the control hub shown in FIG. 16 to push a cutting element 218out of the cutting element deployment arm 216 and into the targettissue. To accomplish this, a simple threaded mechanism 230 as shown inFIG. 16 could be used. This thread 232 would advance the driver rod 222by the length of one cutting element 218 with each rotation of the knob235. The stack of cutting elements 218 is held in the end of the cuttingelement deployment arm 216 by a small elastically deflectable detent237. This can only be pushed back by applying a significant forcethrough the driver rod 222, pushing cutting element 218 past the detent237 and out the end of the cutting element deployment arm 216. As thiscutting element 218 passes by, the detent 237 springs back to block thepassage of the next cutting element 218. This ensures that only onecutting element 214 is deployed at time.

In operation, a user advances the guide wire 114 to a desired location,such as a pulmonary vein 102, as seen in FIG. 14. Next, the catheterbody 214 (within transseptal sheath 106) is advanced along the guidewire 114 until the distal end of the catheter body 214, i.e. theexpandable mesh anchoring section 220, achieves a desired position, suchas within a pulmonary vein 102. The inner sheath 212 is retracted,exposing the cutting element deployment arm 216. The user then advancesthe cutting element deployment arm 216 to the target tissue location,such as the ostium 100 of the pulmonary vein, and actuates the driverrod 222 to deploy a cutting element 218 into the tissue. The cuttingelement deployment arm may be repositioned at varying positions aroundthe catheter body 214 to deploy cutting elements 218 at additionallocations. When cutting element 218 deployment is complete, the userretracts the cutting element deployment arm 216, contracts theexpandable mesh anchoring section 220, and removes the cutting elementdeployment catheter 210 from the patient. As with the devices describedin FIGS. 9 and 10, these deployed cutting elements can be eitherpermanent implants or made of biodegradable materials. They create ascarring healing response both to the mechanical cutting of theirdeployment and also as a response to the material left as an implant.

In yet another preferred embodiment according to this invention, acutting element is coated with a drug or other material which would bedeposited into the cuts made by the elements. In this embodiment thebasic mechanism of scar generation changes from being purely a responseto the mechanical injury and associated bleeding, to being a combinationof the mechanical injury and the response to the drug or material. Somepossible coatings for this embodiment would include glutaraldehyde,tetracycline, actinomycin, and polidocanol, ethanol, talc, or any othersubstance that induces scar formation. Moreover, the device may behollow, with fluid pumped through the system to supply neededconcentrations for scar induction all along the course of the device asit contacts tissue.

Although the invention has been described in terms of particularembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of or exceeding the scope of theclaimed invention. Accordingly, it is to be understood that the drawingsand descriptions herein are proffered by way of example to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

1. A device for causing tissue injury comprising: a tube having afixation element disposed at a distal end of said tube; a deployment armconnected to said tube; a plurality of cutting elements disposablewithin said deployment arm. a mechanism for ejecting at least onecutting element to a target tissue site when said fixation element hasretained said tube in a desired position.
 2. A device as set forth inclaim 1, wherein said fixation element is an expandable mesh.
 3. Adevice as set forth in claim 1, wherein said device is a catheterassembly.
 4. A device as set forth in claim 1, wherein said cuttingelement includes a coating to enhance tissue inflammation.
 5. A deviceas set forth in claim 1, wherein said cutting element includes a coatingto enhance scarring.
 6. A device as set forth in claim 4, wherein saidcoating is selected from a group comprising glutaraldehyde,tetracycline, actinomicin, and polidocanol.